1. Field of the Invention
This invention relates generally to refrigeration isolation valves and more particularly to an integral pair of ball valves close coupled by a union and the use of such combination as an isolation valve for disconnecting and replacing charged refrigeration components.
2. General Background
Commercial refrigeration systems and air conditioning systems have become absolute necessities in commercial ventures around the world. Such systems have become so much of everyday living that we depend on them for our existence and commerce to the point that we can hardly do without them even for short periods of time. These systems seem to break down more often in the hottest times of the year, thereby causing a backlog for the repair industry. Inventories are depleted and systems are down for long periods of time thus prompting repeated service calls. The problem is compounded further in countries where refrigeration service technicians are scarce. In many cases, although it is very simple to diagnose the problem in such systems, it is quite another to obtain essential critical components, especially such expensive components as condensing coils and compressors, and locate experienced technicians to install them immediately when they are needed. In most cases to make such major repairs as replacing a coil or compressor, the technicians must first recover the freon (required in some countries) from the system for disposal under regulated conditions. The technician must then cut the refrigeration lines leading to the component unit, thereby contaminating the system with moist air. When the new component is connected in place by soldiering the lines in an attempt to perfect a perfect seal, which is not always easily accomplished on the first try, the technician must draw a vacuum on the system prior to injecting new freon, all of which takes time and some degree of expertise.
The problem may be as simple as providing precharged components. Therefore, if the system is equipped with isolation valves which allow the refrigeration lines to be disconnected with very little loss of the vital freon gas from either the system or the component element, an experienced technician would not be required to get the system back on line. Further, precharged components could be warehoused more easily and ready for use when they are needed.
Isolation valves such as closed coupled ball valves have been developed as disclosed by Brown and McCracken in U.S. Pat. Nos. 5,332,001 and 5,402,825. These apparatus, although possibly effective in some applications are considerable more complicated and costly than is considered necessary for the application disclosed herein. It is also desirable to have a bleeder port located between the ball assemblies to allow for the purging of air trapped between the two balls when the system is reactivated. These two cited references do not provide such a mechanism nor do they have a method of capping the end of each valve while they are separated, thus preventing the accidental opening of a charged system or component. There is also no indication in these references that they are considered as being gas tight since they rely on a system of springs and seals for swivel alignment of one or both of the ball valves.